Flash vs. HTML5. HTML5 vs. Flash. Whatever your take on the respective merits of the two high-profile technologies for creating splashy Web content, you can’t deny that the rivalry between Adobe’s venerable Flash and the assortment of evolving open-source standards collectively known as HTML5 is intense.

But what if Flash could become HTML5?

Starting now–in certain limited instances–it can. First demoed at Adobe’s MAX conference last October, Wallaby is a free new app from Adobe using its AIR platform that sucks in Flash content created with the Flash Professional authoring software, then spits out an HTML5 version designed to work well in WebKit browsers.

Mind you, Wallaby is an experiment, not a great leap forward. It can only convert simple Flash content like animated ads, not anything that truly takes advantage of Flash’s capabilities for rich, interactive media. Adobe sees its primary applications as being to help designers of Flash ads create HTML5 versions for use on Apple’s iOS devices. (HTML5 versions of ads would also work on any other device with a modern browser, of course, but it might not surprise you to learn that Adobe’s take on the subject is that you only need to covert Flash to HTML5 for use on browsers that don’t support Flash.)

Of course, once a piece of Flash content has been turned into HTML5, you could add interactivity back in using HTML5′s own features in an app such as Adobe’s own Dreamweaver. Adobe says the code that Wallaby outputs is a starting point, not necessarily a finished product.

Here’s a screen shot provided by Adobe of a Flash ad that’s been turned into HTML5–the ad’s up top, and the code’s below.

I asked Adobe Senior Product Manager Tom Barclay if Wallaby might be a precursor to something more ambitious, like features built right into Flash Pro that let Web designers output more ambitious content as either Flash or HTML5. He reiterated that the main idea with this software is to let Flash users dabble with HTML5 conversions and provide feedback to Adobe about what they like, don’t like, need, and don’t need.

I’ll be curious to see what comes next. There’s no question that even Web developers who adore Flash are going to want to dip their toes into HTML5 in the coming months and years; there’s no question that Adobe must create outstanding HTML5 authoring tools if it wants to keep on being the indispensable tech company that it’s been for the past three decades. Whatever happens, it’s going to be fascinating–and Wallaby is a first step in a general direction that seems inevitable to me.